It is the purpose of this project to isolate the messenger RNA for collagen and the attendent RNA and protein moieties which modify colagen biosynthesis. Towards this end several approaches are being taken. Messenger RNA is being extracted from several connective tissue sources, including fetal rat and chick calvaria (Type I collagen) and rat chondrosarcoma (Type II collagen). A number of techniques are being utilized including column chromatography (poly T, poly CCA cellulose, sepharose 4B, poly U sepharose) and immunological procedures. Collagen synthesizing polysomes have been isolated successfully using immune reagents which yield and enriched source of collagen mRNA. Collagen specific tRNAs and translation control RNAs which modulate collagen $ biosynthesis have been detected and are being isolated by differential extraction and column chromatography. Another aspect of the project is the preparation of cDNA from purified mRNA using reverse transcriptase. This will generate a highly sensitive probe for the presence of collagen mRNA in developmental systems and a measure of the number of gene copies in various tissues.